xmas gift ideas for high school boyfriend?

What is your budget?

You need to figure out overall how much you can spend and then consider things he likes or hobbies from there. A video game, sports tickets (semi pro will be a lot more affordable), concert tickets are not cheap so I really wouldn't suggest that unless you have saved up some money, something you can do together (movies, indoor go kart racing, bowling, etc).

I just helped one of my daughter make gift basket for her bf for Christmas. She works part-time so she has her own money and she's a saver so she bought everything herself, I just gave suggestions and helped her shop. She got him a video game he wanted, then bought him things they can do together. She got him a gift card to a bowling alley that has indoor bumper cars, an escape room, obviously bowling and a few other things to do, then also got him a gift card somewhere they can eat together and some candy. So a "want, something do do, something to eat" kind of thing.

You, wrapped in just a bow.

Figure out what your budget is, and maybe call his sister, if he has one, or his mom to get suggestions.

Consider his hobbies (sports, reading, movies, music- what does he like to do?) You don't need to spend alot of money- I am assuming since you are 17 you dont have alot anyway.
buy or rent a movie you both will enjoy, buy some snacks or carry out food and have a fun "date night"
Go to a sports game together, a concert.